1. Field of the Invention
This invention relates to support devices for mounting and supporting electrical resistance heating elements of substantial weight.
2. Background Information
Due to the high degree of current interest in energy conservation, industrial heat process furnaces are being designed with lightweight insulation, usually some form of ceramic fiber. More particularly, one variety of such insulation consists of a ceramic fiber blanket material; another type is a so called vacuum formed ceramic fiber insulating module.
In the design of such electrically heated furnace, an essential problem that must be faced is how to mount and support a resistance element wire to the layers of ceramic fiber insulation that cover the interior of the furnaces. To date, most of the ceramic fiber insulation used has been in the first-noted form of blanket layers applied to the inner surfaces of the furnace shell.
The electric resistance elements are designed in various configurations, the most popular of which is a formed rod of resistant material in the shape of a reversed bend arrangement which must be supported or suspended from the side walls of the insulating material. Since the electric resistance element is of substantial weight, the supporting mechanism tends to become quite complicated, due in part to the fact that these elements cannot be grounded to the furnace's outer steel shell.
One particular form of mounting that is known may be appreciated by referring to a brochure which describes "PYRO-BLOC ELECTRIC ELEMENT SYSTEMS" of Saunders Industries, which is a major producer of fiber-lined furnaces. This element hanger system is useful as a basis of comparison with the present invention. It should be noted that the hanger system described in the brochure or article is adapted to be used with furnace linings consisting of the previously noted refractory or fiber blanket material. Such system involves the use of a ceramic tubing or rods which are buried in the refractory fiber blanket, the tubing being engaged by hooks on a series of spaced rods whose other ends have similar hooks engaging the spaced reverse bend loops of the electric resistance elements.
On the other hand, applicant's invention is particularly adapted to be utilized with the formed ceramic fibers insulating modules sold under the trademark "MOLDATHERM" (owned by Lindberg, Inc., a unit of General Signal). The reason that applicant's invention is especially adapted to the aforenoted modules is that these are produced in approximately 13 pounds per cubic foot density as compared to the ceramic blanket at 6-8 pounds per cubic foot. These ceramic modules are held in shape by a binder which imparts far greater mechanical strength to the refractory fiber and therefore will support the weight of such electrical elements as described.
Accordingly, it is a primary object of the present invention to provide an extremely simple support for an electrical resistance element.
Another object, by reason of the simplicity, is to reduce substantially the cost of the support.